1. Technical Field
The invention relates to the control and monitoring of electric motors and more particularly to a system providing exercising of and failure indicating for a direct current motor.
2. Description of the Problem
Utility vehicles are often advantageously supplied with auxiliary equipment, the operation of which is supported by the vehicle. Such auxiliary equipment can include hydraulically powered, aerial lift platforms as are often used for the repair of electrical power distribution lines. Typically, a hydraulic lift platform will be driven by a primary pump which is in turn driven by the vehicle's engine. In some applications, a back up hydraulic system is provided having a pump powered by a direct current motor energized by the vehicle's battery.
Back up direct current motors fail more often than they should due to harsh,operating environments and infrequent use. Failures of the motors can stem from corrosion between the motor brushes and commutator or from motor bearings seizing. It would be desirable to provide operators of utility vehicles indication of the status of these motors and improve the reliability by limiting the problems caused by lack of regular use.